This invention relates to an. arrangement in a glass bending furnace in accordance with the preamble of claim 1 by means of which arrangement formation of glass sheet unloading and glass sheet loading times are prevented as capacity restricting factors.
Previously known are so called serial type bending furnaces, where the glass sheets move for bending on the upper rail and the bent ones back to the loading and reloading place along the lower rail either in carriages with side walls or in open carriages. In these arrangements both the removal of a bent glass sheet and placing a straight blank in the mould are carried out while said carriage is standing still in the lower part of the so called loading lift.
The circulation time of carriage vertical motions including horizontal motions, lift motions, function of side members etc. typically take ab. 30 sec. Then the carriage is immobile in the lower part of said loading lift depending on the capacity of furnace each time. For instance, at a capacity of n pieces/h the time of standing still is (3600 sec)/nxe2x88x9230 sec.
If, for instance, the required furnace capacity is 60 pieces/h, then there will remain altogether 30 sec time (=15 sec.+15 sec.) for unloading and loading. In this case loading and unloading can still be carried out successfully by experienced persons, but two persons would be needed.
However, if one wants to increase the capacity to a quantity of 100 pieces/h, for instance, the so called cycle length will be 36 sec. and altogether 36 sec.xe2x88x9230 sec.=6 sec. time will remain for loading and unloading, the job is then impossible.
The arrangement as per this invention eliminates the top limit of lifting capacity caused by the loading and unloading procedures.
The invention is characterized in what is presented in the claims.
By means of the arrangement one is not tied to the cycle length in the manner that unloading from and loading into the mould carriage should be carried out within that time. Thanks to the arrangement the capacity of furnace can be increased substantially from known rates of 30-70 pieces per hour in present serial furnaces to a rate of 100-120 pieces per hour. By means of the arrangement both bent glass sheets and straight glass sheets to be loaded into the furnace are more easily handled than the ones today, because the moulds are better pulled forward for the period of glass sheet replacement in a special workplace for glass sheet changing.